Ribbon-reversing mechanism



Nov. 30 1926.

BY A 7641.41, gal/LU,

ATTORNEY UNITED STATES.

ERNST KASSNER, OF BERLIN, GERMANY.

PATENT oFFlc RIBBON-REVERSING MECHANISM.

Application led lay-11, 1926, Serial No. 108,321, and in Germany July 19, 1924.

This invention relates to automatically re-l versing ribbon feed mechanisms and more particularly to such mechanisms as applied to duplex adding machines, cash registers and the like. An object of the invetion is to facilitate the changing of the ink ribbon. Other objects of the invention are to improve the ribbon feed device and the mechanism for'reversing the direction of the travel `of the ribbon.

These objects are accomplished according to the invent-ion byl arranging the ribbon spools on a spool carrier mounted on a slidable support adapted to passl out through the side of the machine and by making revtractible the ends of the feelers that are known per se and that contact with the ribbon coils and control the ribbon reversing mechanism. The retractible ends of the feelers are arranged to .be drawn in to such lan extent as to be removable from the path of the ribbon spool ends when the spool carlrier is protruded through the Side of .the machine to enable the ribbon to be changed. Each of the two feelers acts through intermediate members on an associated spool operating device. or reciprocating feed bar so as to lock the feed bar against further operation when a certain amount of ribbon has been wound up by the spool and at the same time the feed bar of the other spool is released to enable it to step this spool round. The reversing mechanism is constructed so that 4its action is independent of inaccuracies in the winding up of the ink ribbon and -its reversing action is perfectly positive in allv circumstances. Furthermore it is arranged to be automatically locked when a ribbon spool is taken out or replaced.

One form of the novel ink ribbon mechanism is shown by way of example in the drawing in which- Fig. 1 shows a; cross section through a A'part of a duplex adding machine equlpped with a ribbon mechanism, and

Fig. 2 is a plan view of the mechanism shown in Fig. 1.

The motion for the parts of the mechaniSm is derived from the shaft 1 which, by means of the connecting rod 3* and the lever l 3, is oscillated or turned to and fro round its axis once at each revolution of the main driving shaft (not shown). When the shaft 1 is oscillated clockwise a' .cam or striker 2v p down a spool operating memberar- 13 and 4a disk 15 rigidly attac ranged at a side ofthe machine and constructed in the form of a vertical reciprocable stepping bar or feed bar 4 which is ,guided by pins 10 and 11 protruding lof the arm or striker 3 on the vertical reciprocable feed bar 5 situated at the opposite side of the machine, but this action only takes place when this latterbar 5 is not locked in its lowermostposition in a manner described hereinafter. 'According to the direction of travel of the ink ribbon, the one or the other of the reciprocable bars 4 or 5 is always locked in its lowermost position by means of its catch 4a and a. locking member 33 or 34 as will be hereinafter more fully described. Mounted on each of the reciprocable bars is a stepping pawl 6 adapted to oscilla-te on apivot `7 and to engage with the teeth of a-stepping wheel 12 or 13 that forms an end of a ribbon spool. The stepping pawl 6 on each reciprocable feed bar is held in its operative or stepping position by a pin 6a that protrudes into a hole in the' rear end of the pawl. When'the pawl executes a backward motion the hole permits it to 'oscillate slightly on i-ts ivot so that it may move past the-teeth of t e stepping wheel 12 or 13 with which it is associated.

The stepping wheel 12, and a disk 14 rigidly attached thereto, form one ribbon spool or the space therefor .and the stepping wheel ed thereto form a second ribbon spool. These spools turn freely on pivots 16 carried by spool carrying arms integral with or attached to a slidable support 17 which 1s arranged to slide on a fixed guide plate 18 t'o which the support 17 is attached by guide screws 17.

Projecting into the spaces between .the ends of the spools are the feeler members 19 and 20 which are arranged to rock on pivots 19h and 20", and are provided with shoes or retractible ends 19 and 20* that canbe shortened or drawn in'suiliciently to be out of the path of'the ends of the ribbon s ools when these spools are lmoved latera ly .as hereinafter described. When the retractible ends are in their normal positions they are held there by screws 21. To enable a ribbon spool to'bemoved laterally with its carrier 17 through the side of the machine the screw 21 of the end or shoe 19a or 20"1 is loosened and the retractible end is then slipped back on its arm 20 out of the path of the spool. Y v

The feelers 19 and 20 are constructed in the form of two-armed levers whose rear arms are attached by slot and pin connections to the reversing members which have the form of sliding bars 22 and 23. These bars each extend along a side of the machine to a certain point where they bend inward and extend towards the middle of the machine where they bend again in the lengthwise direction of the machine and there form two adjacent parallel middle sections 22a and 23a. The front ends of the sliding bars 22, 23 slide upon inwardly projecting platforms 24, 24a and their slotted adjacent rear ends are guided by a transverse bar or shaft 25. Attached to the adjacent sections '223, 23L of the sliding reversing bars 22 and 23 are stops 26 and 27 that cooperate with a detent 28 maintained under pressure by a spring 29, which detent controls the changeover or reversing operation of the reversing bars as follows: Vhen the one or the other reversing bar is moved, in the manner hereinafter described, a certain distance towards the left, an inclined surface 26a or 27 of a stop 26 or 27 respectively lifts the pivoted detent 28 and then allows it to drop behind the vertical surface 261 or 27 b in which position it limits the movement of the particular sliding reversing bar that is pulled towards the right by its spring; for both reversing bars 22, 22b and 23, 23b have springs 31 and 32 attached to the shaft 25 that exert a, pull on the reversing bars towards the right. Hence when, during its forward movement one of the reversing bars,

v by the inclined surface of its stop, lifts the detent 28 this detent releases the other reversing bar that, up to that moment, has been locked and allows it to be pulled backward or towards the right by its spring.

A function of the sliding bars 22 and 23 is to render inoperative or to lock the particular reciprocable'feed bar 4 or 5 whose associated ribbon spool is being unwound. For this locking function each of the feed bars is provided at its bottom vend with a catch 4 that is adapted to be caught by spring locking members 33 and 34 respectively when the particular sliding bar reaches its furthermost left position. The shifting of a sliding bar into its furthermost left pesition is performed by shifting means or members consisting of a pivoted wedge-shaped member 30 mounted on the inner surface of its associated reciprocahle feed bar and a cooperating0 wedgeshapef member 36 or 36a attached y a bolt to the @iter surface of the associated sliding reversing bar.

Each of the wedge-shaped the spring 8 that draws the associated reciprocable bar, as 4, upwards and pulls the said `arm of the wedge-shaped member round against a stop-pin 35. The left oblique surface of each wedge-shaped member 30 is parallel to the right hand oblique surface of its 'cooperating wedge-shaped member 36 or 361. When the diameter of the coil of ribbon on a spool has grown to such an extent as to swing its contacting feeler 19a into a position in which it pushes the point or edge of the wedge-shaped member 36 of a sliding reversing bar 22 slightly beyond the edge of the wedge-shaped member 30 on the associated reciprocable feed bar 4, the next downward movement of the bar 4 caused by the striker 2 results in the oblique surfaces of the wedges 36 and 30 sliding upon each other and imparting the final shifting movement to the reversing bar 22. This in turn results in the detent 28 being lifted suliiciently to release the stop 27b of the other reversing bar 23 whose. spring 32 now draws it into its extreme right position. In thus moving to the right, the locking member 34 on the bar 23 releases the catch 4a of the feed bar 5 which is then raised from its bottom inoperative position into the position in which the striking surface 3b of the oscillating arm 3 of the shaft 1 can act upon it to cause it to begin stepping its ribbon spool which then moves the ribbon in the reverse direction. The sliding bar that is associated with the operating reciprocable feed bar is shifted into its extreme left position and the other sliding bar is released in its turn as described when the coil on the spool thatL is now empty has grown to the predetermined extent. By the described arrangement for imparting the final shiftingv movement to the reversing bars by the operation of the reciprocable bars, the reversing operation is made independent of an accurate winding up of the ink ribbon and it is thus made to be a mechanical function that is performed with certainty.

In line with the spool carrier or slidable support 17 openings are provided in the machine casing A that are usually closed by doors B. l/Vhen the doors are closed they act upon two-armed levers or dogs 37 and 38 thus forcing their bottom arms 37", 38b out of the path of holding members or projeetions 39 and 40 on the reversing bars 22 and 23. The levers 37 and 38 are provided with torsional springs 37, 38a which, on' the doors B being opened, turn the bottom arms 37b, 381 of the dogs into the path of the holding members 3S), 40 and thus lock the reversing bars against movement when the spool carrier is slipped out to enable a ribbon to be renewed. By this means the shifting of the reversing bars 22, 23 by manually moving the feelers 19, 2O when the doors are members 30 has an arm to which is attached llO opened isprevented, for when the spool carrier is taken outthe reversing mechanism is locked.

1. In a machine of the class described, an

automatically reversing ribbon-feed mechanism comprising a pair of ribbon spools one at each side of the machine and each provided with a ratchet wheel, said spools being secured on a common shifting spool carrier, a pair of feeler memberseach having a retractible end portion adapted to contact with the ribbon on one o f said spools, and means for retracting said end portions alternately whereby only one of said portions is in contact with its spool at any given time, thereby to release the spool and its carrier for movement'laterally of the machine. r

2. In a machine of the kind described, an automatically-reversing ribbon-.feed mechanism comprising, two ribbon spools, each provided with a ratchet wheel, at the two sides of the machine, a reciprocating bar with a stepping-pawl cooperating wit-h each ratchet wheel, a reversing bar for each reciprocating bar, a spring for each reversing bar, a eeler member for each spool with a retractible end that contacts with the ribbon on its spool and moves an associated reversing bar a ainst the draught of its spring as the size o the coil of ribbon changes, a catch on each reciproca-ting bar and a locking member that cooperates therewith on the corresponding reversing bar, shifting members on each reciprocating bar, and reversing bar which operate Vwhen a reversing bar has been moved forward sufficiently by its feeler bar to shift the 'reversing bar into a position in which its locking member engages With the catch on the corresponding reciprocatin bar and locks the latter so as to revent urther operation of its associate spool, and means-for simultaneously enabling the other reversing bar to be moved back by its spring from its locking position and for thus starting the operation of the other reciprocating ar and its associated spool substantially as described.

v3. n a machine of the kind described, an automatically-reversing ribbon-feed mechanism comprising, two ribbon spools, each provided with a ratchet wheel, at the two sides 1' f the machine, a 'reciprocating bar with 'a stepping pawlcooperating with each ratchet wheel, a'reversing bar for each reciprocating bar, a spring for each reversing bar, a feeler vmember for eachl spool with a retractible end that contacts with the ribbon on its spool and moves an associated reversing bar a ainst the draught of its spring-as the size o the coil of ribbon changes, a catch on each reciprocating bar and a yielding, spring, locking member that cooperates t erewith on the corresponding reversing bar, shifting members on each reciprocating bar, land revers' a reversing bai-Das been moved forward sufficiently by its feeler bar to shift the reversing bar into a. position in which its spring locking member engages with the catch on the corresponding reciprocating bar and locks the latter so as to prevent further operation of its associated spool, and mea-ns for simultaneously enabling the other reversing bar to. be moved back by its spring from its locking position and for thus starting the operation of the other reciprocating bar and its associated spool, substantially as described.

4. In` a machine of the kind described, an yautomatically-reversing ribbon-feed mechanism' comprising, two ribbon spools, each provided with a ratchet wheel, at the two sides of the machine, a reciprocating bar with a stepping pawl cooperating with each ratchet wheel, a reversing bar for each reciprocating bar, each reversing bar extending along tli'e side of the machine to a certain point where it bends inward towards the middle of the machine and then again extends lengthwise so that the two reversing bar which operate when bars have adjacent sections in close proximity to each other extending along the middle of the machine, a spring for each reversing bar', a feeler member for each spool with a retractible end that contacts with the ribbon on its spool and seizes an associated reversing bar to move it against the draught of its spring as the size of the coil of ribbon changes, a catch on each reciprocating bar and a locking member that cooperates therewith on the corresponding reversing bai', shifting members on each reciprocating bar and reversing bar which operate when areversing bar has been moved forward suiiiciently by its feeler bar to shift `the reversing bar into a position in which its locking member engages with the catch on the corresponding lreciprocating bar and locks the latter so as to prevent further operation of its associated spool, a stop on each said adjacent section, and a detent cooperating with said stops for holding` the other reversing bar in its locking position against thedraught of its spring untilI the first reversing bar is shifted into its locking position.

5. In a machine of the kind described,-'an automatically-reversing ribbon-feed mech- Janism comprising, two ribbon spools, each provided with a ratchet wheel, at the two sides of the. machine, a reciprocating bar with a stepping pawl cooperatin with each ratchet wheel, a reversing bar or each reciprocating bar2 each reversin bar extendity to each other extending along the middle of the machine, a spring for each reversing vbar, a eeler member for each spool with a retractible end that contacts with the ribbon onits spool and seizes an associated reversing bar lo move it against the draught of its spring as the size of the coil of ribbon changes, a catch on each reciprocating bar and a locking memberV that cooperates therewith on the corresponding reversing bar, shifting members on each reciprocating bar and reversing bar which operate when a reversin bar has been moved forward suficientlygby its eeler bar to shift the reversing bar into a position in which its locking member engages with the catch on the corresponding reciprocating bar and'. locks the latter so as to prevent further operation of its associated spool, a stop with a sloping and a vertical engaging surface on each said adjacent lsection, and a detent adapted to cooperate with said stops, the sloping surface of one said stop being adapted to lift the detent from engagement with the vertical surface of the other stop so as to allow it and its reversing barto be withdrawn by its spring from its locking position when the other reversing bar 1s shifted into its locking position and held there by said. detent until the rst reversing bar is moved forward byits iecler bar into its locking position.

6. In a machine of the kind described, an automatically-reversing ribbon-feed mechanism comprising, two ribbon spools, each provided with a ratchet wheelVat the two sides of the machine, a reciprocatingbar with a stepping pawl cooperating with each ratchet wheel, a reversing bar for each reciprocating bar, each reversing bar extending along the side of the machine to a certaln point where it bends inwards towards the middle and then extends lengthwise again so that the reversing bars have two adjacent sections extending lengthwise along the middle of the machine, a spring for each reversing bar, a feeler member for each spool with a retractible end that contacts with the ribbon on its spool and moves an associated reversing bar against the draught of its spring as the size of the coil of ribbon changes, a catch on each reciprocating bar and a locking member ythat cooperates therewith on the corresponding reversing bar, each reciprocating bar vand its associated reversing bar being provided with wedgeshaped cooperating cams for shifting the reversing bar into a position in which its locking member engages with the catch on the associated reciprocating bar and thereby locks the latter so as to prevent further Voperation of its associated spool, a stop on each of the two said adjacent sections ol' the reversing bars, and a detent that cooperates with said stops to hold the one reversing bar in its locking position While releasing the other' reversing bar to allow it to be retracted by its spring so as to release itsl associated spool-stepping ,reciprocatingI bar, substantially as described.

7. In combination with a machine of the kind described, a ribbon-feed mechanism comprising two ribbon spools one at each side of the machine, pivots for carrying said spools and off which the spools can be slipped, spool carriers on which said pivots are mounted, a slidable support for the spool carriers, doors for openingsin the machine sides through which the slidable support with the spool carriers can be passed to enable the spools to be removed, a spool operating member for each spool, a reversing mechanism for alternately stopping and starting the operation of the spools, and means for preventing the operation of said reveising mechanism when a said door is opened, substantially as described.

8. In combination with a machine of the kind described, a ribbon-feed mechanism` comprising two ribbon spools one at each side of the machine, pivots for carrying said spools and o which the spools can be slipped, spool carriers on which said pivots are mounted, a slidable support for the spool carriers, doors for openings in the sides of the machine through which the slidable support with the spool carriers can be passed to enable the spools .to be removed, a spool operating member for each spool, two movable reversing bars, one for each spool, for alternately 'stopping and starting the two spool operating members, a holding member on each reverslng bar, and a dog at each side holding member to prevent the `operation of its reversing bar when an adjacent saiddoor is opened, substantially as described.

In testimony whereof I have signed my of the machine for engaging with a said Y 

